Field of the Invention
The present invention relates to a cleaning apparatus that removes toner remaining on photosensitive drums, a process cartridge, and an image forming apparatus.
Description of the Related Art
In image forming apparatuses proposed in the prior art which employ an electrophotographic technique, toner images formed on photosensitive drums are transferred to a recording medium so as to form images on the recording medium (U.S. Pat. No. 8,594,527). In many cases, such image forming apparatuses are provided with a cleaning apparatus that collects remaining toner which remains on the photosensitive drums after the toner images have been transferred. The cleaning apparatus includes a cleaning member that removes the remaining toner on the photosensitive drums, a collection container in which the remaining toner is contained, and a collection sheet member that restrains the remaining toner in the collection container from leaking to the outside of the collection container.
In the prior art, vibration of the cleaning member may cause “noise”. Such occurrence of noise is undesirable to users who use the image forming apparatus in an office environment. The noise occurs when the photosensitive drums and a developing apparatus become worn away, increasing a coefficient of friction μ of the surfaces of the photosensitive drums. An increased coefficient of friction μ of the surfaces of the photosensitive drums causes a stick-slip of the cleaning member. The resultant vibration is transmitted to the collection container to cause the noise. Stick-slip is a spontaneous vibration resulting from repeated adhesion and slippage between friction surfaces. To suppress the noise, the coefficient of friction μ of the surfaces of the photosensitive drums needs to be kept small from the first use of the photosensitive drums until the lives of the photosensitive drums come to an end.
In Japanese Patent Application Laid-open No. H4-245285, a coating layer containing lubricative particles is provided in a part of a collection sheet member that contacts the photosensitive drum. Herein, the lubricative particles are fed from the collection sheet to the surface of the photosensitive drum to reduce the coefficient of friction μ of the surface of the photosensitive drum. The reduced coefficient of friction μ of the surface of the photosensitive drum suppresses noise resulting from vibration of the cleaning member.
However, the invention disclosed in Japanese Patent Application Laid-open No. H4-245285 requires an operation of forming the coating layer containing the lubricative particles and, moreover, material costs for the lubricative particles are high, these aspects leading to an increase in the production costs for the image forming apparatus.